# -*- test-case-name: twisted.conch.test.test_manhole -*-
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
insults/SSH integration support.

@author: Jp Calderone
"""

from typing import Dict
from zope.interface import implementer

from twisted.conch import avatar, interfaces as iconch, error as econch
from twisted.conch.ssh import factory, session
from twisted.python import components

from twisted.conch.insults import insults


class _Glue:
    """
    A feeble class for making one attribute look like another.

    This should be replaced with a real class at some point, probably.
    Try not to write new code that uses it.
    """

    def __init__(self, **kw):
        self.__dict__.update(kw)

    def __getattr__(self, name):
        raise AttributeError(self.name, "has no attribute", name)


class TerminalSessionTransport:
    def __init__(self, proto, chainedProtocol, avatar, width, height):
        self.proto = proto
        self.avatar = avatar
        self.chainedProtocol = chainedProtocol

        protoSession = self.proto.session

        self.proto.makeConnection(
            _Glue(
                write=self.chainedProtocol.dataReceived,
                loseConnection=lambda: avatar.conn.sendClose(protoSession),
                name="SSH Proto Transport",
            )
        )

        def loseConnection():
            self.proto.loseConnection()

        self.chainedProtocol.makeConnection(
            _Glue(
                write=self.proto.write,
                loseConnection=loseConnection,
                name="Chained Proto Transport",
            )
        )

        # XXX TODO
        # chainedProtocol is supposed to be an ITerminalTransport,
        # maybe.  That means perhaps its terminalProtocol attribute is
        # an ITerminalProtocol, it could be.  So calling terminalSize
        # on that should do the right thing But it'd be nice to clean
        # this bit up.
        self.chainedProtocol.terminalProtocol.terminalSize(width, height)


@implementer(iconch.ISession)
class TerminalSession(components.Adapter):
    transportFactory = TerminalSessionTransport
    chainedProtocolFactory = insults.ServerProtocol

    def getPty(self, term, windowSize, attrs):
        self.height, self.width = windowSize[:2]

    def openShell(self, proto):
        self.transportFactory(
            proto,
            self.chainedProtocolFactory(),
            iconch.IConchUser(self.original),
            self.width,
            self.height,
        )

    def execCommand(self, proto, cmd):
        raise econch.ConchError("Cannot execute commands")

    def windowChanged(self, newWindowSize):
        # ISession.windowChanged
        raise NotImplementedError("Unimplemented: TerminalSession.windowChanged")

    def eofReceived(self):
        # ISession.eofReceived
        raise NotImplementedError("Unimplemented: TerminalSession.eofReceived")

    def closed(self):
        # ISession.closed
        pass


class TerminalUser(avatar.ConchUser, components.Adapter):
    def __init__(self, original, avatarId):
        components.Adapter.__init__(self, original)
        avatar.ConchUser.__init__(self)
        self.channelLookup[b"session"] = session.SSHSession


class TerminalRealm:
    userFactory = TerminalUser
    sessionFactory = TerminalSession

    transportFactory = TerminalSessionTransport
    chainedProtocolFactory = insults.ServerProtocol

    def _getAvatar(self, avatarId):
        comp = components.Componentized()
        user = self.userFactory(comp, avatarId)
        sess = self.sessionFactory(comp)

        sess.transportFactory = self.transportFactory
        sess.chainedProtocolFactory = self.chainedProtocolFactory

        comp.setComponent(iconch.IConchUser, user)
        comp.setComponent(iconch.ISession, sess)

        return user

    def __init__(self, transportFactory=None):
        if transportFactory is not None:
            self.transportFactory = transportFactory

    def requestAvatar(self, avatarId, mind, *interfaces):
        for i in interfaces:
            if i is iconch.IConchUser:
                return (iconch.IConchUser, self._getAvatar(avatarId), lambda: None)
        raise NotImplementedError()


class ConchFactory(factory.SSHFactory):
    publicKeys = {}  # type: Dict[bytes, bytes]
    privateKeys = {}  # type: Dict[bytes, bytes]

    def __init__(self, portal):
        self.portal = portal
